Many devices have been proposed and manufactured for automatic dispensing of cleaning liquids into flush toilets. For example US20040128750 discloses an automatic liquid dispenser dispenses precisely measured amounts of cleaner/deodorizer into a toilets tank through a closed system is further disclosed. The invention consists of a housing that connects between the water supply line and the water supply inlet of a toilets tank and a refillable liquid storage container. The housing is installed in the flow path of the water supply used to fill a toilets tank for flushing. During the filling of the toilets tank the flow of water is directed over an orifice causing a siphon to be created. This siphon compresses a spring loaded ball check allowing liquid cleaner/deodorizer to flow into the water supply filling the toilets tank When the tank is full it contains a predetermined and precisely mixed amount of water and cleaner/deodorizer.
US20060242754 discloses a toilet cleaner dispenser system is centered above an overflow tube and configured to deliver cleanser solution directly to the overflow tube without a hose. A disposable cartridge containing a cleanser tablet is removably coupled to a dispenser housing. Refill water is directed to the housing through an inlet and brought into contact with the cleanser tablet to form a cleanser solution. The cleanser solution exits an outlet of the housing into a receptacle which directs the solution downwardly and directly into the overflow tube. Inlet and outlet water traps prevent fumes from escaping the housing.